Water is beneficial and vital to all life. Indeed, the importance of hydration to overall health and fitness cannot be overestimated. Approximately 60% of the human body is water, and each organ and system requires ample hydration to function properly. From the regulation of body temperature to the proper digestion of food, and even the cushioning and lubrication of bones and joints, water is essential.
Proper hydration also helps the kidneys and liver function properly. The kidneys need water to remove toxins, waste and salt from the blood. When hydration is poor, the liver takes on some of the removal work load of the kidneys and isn't able to properly metabolize excess fat from the body. In addition, water keeps blood from thickening and in return helps the heart function at its peak. Keeping the body properly hydrated helps the heart more easily pump blood through the blood vessels to the rest of the body. Thus, water plays an important role in cardiovascular fitness as well.
Reliably clean water is equally important. The water supply may contain grit, dirt, sediment and rust, or even harmful bacteria and contaminants. Chlorine is typically added to municipal water supplies to stave off harmful or deadly microorganisms. The addition of chlorine to the water supply has been the standard in water treatment since the early 1900s because of its ability to purify the water and destroy waterborne pathogens. The use of chlorine as a purifier, however, is not without its drawbacks. For example, not only does chlorine leave a bad taste and odor in tap water, some studies show that long term exposure to chlorinated drinking water has been linked to increased cancer risk.
Unhealthy levels of other contaminants found in both municipal and well-water supplies also interfere with water's healthy role, reduce the ability of the body to function properly, and can even kill in extreme amounts. Exposure to zinc can cause nausea and vomiting, and the long term effects of anemia and pancreatic damage. While exposure to cadmium, can cause liver damage. Similarly, exposure to copper can cause gastrointestinal distress, and both liver and kidney damage. Finally, exposure to mercury, which is believed to seep into the water supply via landfills, can lead to kidney damage over time.
Bottled water is a quick and convenient solution for clean drinking water, but the expense adds up over time and bottled water requires additional storage space. Discarding plastic water bottles is also wasteful and considered by many to be an environmental blight. A more permanent and cost-effective solution is offered by water filters.
Water filtration has thus become common in homes, offices and other places to produce cleaner and better tasting water. One popular filtration system is used in conjunction with a water pitcher. Some water pitchers include an upper chamber for holding untreated water and a lower chamber for holding treated water that has exited the upper chamber. A filter cartridge is placed in a fluid path between the two chambers so that untreated water exits the upper chamber via gravity, flowing through the filter cartridge, and entering the lower chamber as filtered water.
The filter cartridge typically resides in a receptacle defined by a candle that is located at the bottom of the upper chamber and that is open to both the upper and lower chambers. The filter cartridge includes openings that allow unfiltered water to enter the interior of the filter cartridge where the unfiltered water comes into contact with a filtering medium that acts to remove contaminants from the water as the water flows through the interior of the filter cartridge. Filter cartridges often include a set of air vents at, or near, the top of the filter cartridge which allow air in the filter cartridge to escape as fluid flows into the filter cartridge.
As filtering is completed, the filtered water exits the filter cartridge into the lower chamber. Treated water is then available and ready to be poured from the water pitcher for consumption by a user. Typically, the filter cartridge is removable so that it can be removed and replaced after the usable life of the cartridge.
The filtering medium in such gravity driven, pour-through filters is generally a combination of granular activated carbon (GAC) mixed with ion exchange resins, which remove impurities from the water via adsorption. That is, the activated carbon and ion exchange resins attract and adsorb particles in the water, resulting in better tasting and cleaner water. These filtering materials work together to reduce chlorine taste and odor, zinc, and other harmful contaminants such as copper, mercury and cadmium from the water supply.
As with any pour-through system, however, there is a limited amount of surface area within the filter for adsorbing particles, resulting in the need for periodic changing of the filter cartridge. One drawback to such filters is that the surface area of the filtering media may be reduced by water being poured over the filter. As the inrushing water enters the air vents, the relatively high velocity of that water causes compaction of the filtration media within the filter cartridge.
Compaction is also inherent in these types of filter cartridge configurations containing granular media since there is the need to have a certain minimum amount of granular media to be packed within a small amount of confined space in point-of-use water filtration systems such as pitchers for performance related to contaminant reduction. This compaction reduces the overall surface area available for filtration, thus reducing the effectiveness of the filtration media. Compacted filtration media also presents increased resistance to the fluid that is to be filtered, such that the rate of fluid flow through the filtration media is compromised.
Incoming water may also directly impinge upon the air vents, effectively blocking the air vents and thus preventing the escape of air from the filter cartridge. Because air is prevented from escaping the filter cartridge, a static, or near static, condition results where water cannot easily enter the filter cartridge. This condition is sometimes referred to as airlock and slows the rate at which water flows through the filter cartridge effectively delaying the availability of filtered water.
Yet another drawback of pour-through filters is the possibility of filter media escaping the filter. In the case of activated charcoal, the smallest particles can escape the filter via the inlet and outlet ports resulting in the appearance of black flecks in the filtered water. Although generally harmless, the presence of such particles on the surface of, or suspended in, the filtered water is unsightly and undesirable to the user.
In view of the foregoing, it would be useful to provide a filter cartridge that provides for an improvement in contaminant reduction performance, relative to legacy designs for example, without materially compromising the flow rate of liquid through the filter cartridge. It would also be useful for the filter cartridge to be able to be readily employed in currently available fluid filtration systems without requiring any modification to the structure or operation of those systems.